Novel Peptides and Analogs for Use in the Treatment of Oral Mucositis

ABSTRACT

Preclinical data obtained in models of chemotherapy-induced mucositis, radiation-induced mucositis, neutropenic infection and colitis indicate oral mucositis is a promising indication for Innate Defense Regulator (IDR) peptides. Preclinical efficacy results obtained with IDRs in mouse and hamster models of mucositis indicate that dosing every third day should be able to cover the mucositis “window” with seven to fourteen doses, depending on the duration of chemotherapy or radiation exposure. IDRs have also shown efficacy in mouse models of chemotherapy-induced oral and gastrointestinal mucositis, consistent with the response of the innate immune response to chemotherapy and/or radiation damage. IDRs are also effective at reducing bacterial burden and improve survival in the presence or absence of antibiotic treatment in various murine infection models.

RELATED APPLICATIONS

This application claims priority from U.S. Provisional Application No.61/877,767, filed on Sep. 13, 2013, the contents of which are herebyincorporated by reference herein.

INTRODUCTION Innate Immune System

The innate immune response is an evolutionarily conserved protectivesystem associated with the barriers between tissues and the externalenvironment, such as the skin, the orogastric mucosa and the airways.Providing rapid recognition and eradication of invading pathogens aswell as a response to cellular damage, it is often associated withinflammatory responses and is a key contributor to the activation ofadaptive immunity. Innate defenses are triggered by the binding ofpathogen and/or damage associated molecules (PAMPs or DAMPs) topattern-recognition receptors, including Toll-like receptors (TLRs).Pattern recognition receptors are found in and on many cell types,distributed throughout the body in both circulating and tissue residentcompartments, and serve to provide early “danger” signals that lead tothe release of non-specific antimicrobial molecules, cytokines,chemokines, and host defense proteins and peptides as well as therecruitment of immune cells (neutrophils, macrophages, monocytes) in ahighly orchestrated fashion (Janeway 2002; Beutler 2003; Beutler 2004;Athman 2004; Tosi 2005; Doyle 2006; Foster 2007; Matzinger 2002).Moreover the innate immune system is directly involved in the generationof tolerance to commensal microbiota in the gastrointestinal tract andin gastrointestinal repair and immune defense (Santaolalla, 2011; Molloy2012).

Mucositis

Mucositis is the clinical term for damage done to the mucosa byanticancer therapies. It can occur in any mucosal region, but is mostcommonly associated with the mouth, followed by the small intestine.Though many mucositis scales are used clinically, the two most commonlyused grading systems are the NCI and WHO scales.

The mechanisms of mucositis have been extensively studied and have beenrecently linked to the interaction of chemotherapy and/or radiationtherapy with the innate defense system (Sonis 2010). Bacterial infectionof the ulcerative lesions is now regarded as a secondary consequence ofdysregulated local inflammation triggered by therapy-induced cell death,rather than as the primary cause of the lesions. Mucositis affects500,000 people in the US per year and occurs in 40% of patientsreceiving chemotherapy (Sonis 2010, Curr. Op.). Mucositis almost alwaysoccurs in patients with head and neck cancer treated with radiationtherapy (>80% incidence of severe mucositis) (Elting et al. 2008).Mucositis is common (40-100% incidence) in patients undergoing high dosechemotherapy and stem cell transplantation (SCT) where the incidence andseverity of mucositis depends greatly on the nature of the conditioningregimen used for myeloablation (Murphy 2007). Of well-establishedchemotherapy drugs, 5-FU and irinotecan are particularly noted forcausing mucositis but it also occurs with newer agents such as mTORinhibitors and kinase inhibitors (Mateus et al. 2009; Sankhala et al.2009). Mucositis can be seriously debilitating and can lead toinfection, sepsis, the need for parenteral nutrition and narcoticanalgesia. The intestinal damage causes severe diarrhea. These symptomscan limit the doses and duration of cancer treatment, thus leading tosub-optimal treatment outcomes including reduced survival. Direct andindirect consequences of mucositis have been estimated to add ^(˜$)18Kper patient to cancer treatment costs (Nonzee et al. 2008). Mucositisoccurs 3-12 weeks after the initiation of radiation, or 3-12 days afterthe initiation of chemotherapy, and resolves after 2-3 weeks, assumingno further chemotherapy or radiation treatment is undertaken.

RIVPA (SEQ ID NO. 5) is an IDR (Innate Defense Regulator), a new classof short, synthetic peptides with a novel mechanism. Designed to mimicone of the recently discovered functions of natural mucosal defensepeptides, IDRs have no direct antibiotic activity but modulate hostresponses, increasing survival after infections with a broad range ofbacterial Gram-negative and Gram-positive pathogens, as well asaccelerating resolution of tissue damage following exposure to a varietyof agents including bacterial pathogens, trauma and chemo- orradiation-therapy.

Based on preclinical data obtained in models of chemotherapy-inducedmucositis, radiation-induced mucositis, neutropenic infection andcolitis, oral mucositis is a promising indication for RIVPA (SEQ ID NO.5) and other IDR peptides. Since the drug would be given soon after thechemotherapy infusion or radiation, the IV dosage form of RIVPA (SEQ IDNO. 5) is well suited to the mucositis indication. Preclinical efficacyresults obtained with RIVPA (SEQ ID NO. 5) in mouse and hamster modelsof mucositis indicate that dosing every third day should be able tocover the mucositis “window” with seven to fourteen doses, depending onthe duration of chemotherapy or radiation exposure.

With regard to breast cancer, ^(˜)20% of patients receiving ACT therapysuffer ulcerative mucositis during their first round of chemotherapy but^(˜)70% of that subset of patients will have ulcerative mucositis ontheir second round (Sonis 2010). This represents a “high risk” patientpopulation that would benefit from RIVPA (SEQ ID NO. 5) treatment. Thereare currently no systemic agents approved for the amelioration ofmucositis in this population.

Patients undergoing high dose chemotherapy and SCT for the treatment ofhematologic cancers are an immunosuppressed population at high risk ofinfection. In this treatment, high doses of chemotherapy (sometimes incombination with radiation), a “conditioning regimen”, are used to killa large proportion of the cancer cells. These treatment levels wouldcause lethal myelosuppression unless stem cells (from bone marrow orblood) are administered afterwards to allow reconstitution of bloodcells. Autologous transplants use the patient's own stem cells for thispurpose while allogeneic transplants use cells from a matched healthydonor. Autologous transplants are used most often in the treatment ofMultiple Myeloma (MM) and non-Hodgkins Lymphoma (NHL). Allogeneictransplants are typically used to treat leukemias such as AML.

With regard to SCT, until recently the various conditioning chemotherapyregimens all resulted in a relatively high rate of oral mucositis(40-100%) and in most US centers these patients are managed in-hospital.Oral mucositis associated with radiation and/or chemoradiation therapyfor head & neck cancer is a major problem, with 85% of subjectssuffering some degree of mucositis—42% being grade 3 or 4.

Acute Radiation Syndrome

Acute radiation syndrome (ARS) is a serious illness that occurs when theentire body (or most of it) receives a high dose of radiation, typicallyover a short period of time. Many survivors of the Hiroshima andNagasaki atomic bombs in the 1940s and many of the firefighters whofirst responded after the Chernobyl Nuclear Power Plant accident in 1986became ill with ARS (CDC 2013).

Individuals exposed to radiation will get ARS only if the:

-   -   the radiation dose was high (doses from medical procedures such        as chest X-rays are too low to cause ARS),    -   the radiation was penetrating (that is, able to reach internal        organs),    -   the person's entire body, or most of it, received the dose, and    -   the radiation was received in a short time, usually within        minutes.

Radiation induces dose-proportional injury to mammalian cells andtissues. At low doses, the injury may be limited to point mutations insomatic and/or germ-line DNA that may be associated with long-termeffects such as an increased risk of cancer or birth defects. Atintermediate doses, radiation induces chromosomal abnormalities such asbreaks and translocations, which again increases the risk of cancers andbirth defects, and if severe enough will result in the death of rapidlydividing cells within hours of exposure. At very high doses, radiationcan denature proteins, resulting in almost immediate death of cells andtissues. The tissues with rapidly dividing cells that are the mostcommonly affected by moderate doses of radiation include the bonemarrow, the gastrointestinal tract and the testis. Exposure to radiationis associated with acute effects, including skin rashes and burns, bonemarrow failure, including anemia, depressed white blood cell counts, andthrombocytopenia, as well as gastrointestinal toxicity such as diarrhea,and more chronic effects such as the development of tumors, especiallysarcomas and leukemias, and birth defects.

The first symptoms of ARS typically are nausea, vomiting, and diarrhea.These symptoms will start within minutes to days after the exposure,will last for minutes up to several days, and may come and go. Then theperson usually looks and feels healthy for a short time, after which heor she will become sick again with loss of appetite, fatigue, fever,nausea, vomiting, diarrhea, and possibly even seizures and coma. Thisseriously ill stage may last from a few hours up to several months.

People with ARS typically also have some skin damage. This damage canstart to show within a few hours after exposure and can includeswelling, itching, redness of the skin and hair loss. As with the othersymptoms, the skin may heal for a short time, followed by the return ofswelling, itching, and redness days or weeks later. Complete healing ofthe skin may take from several weeks up to a few years depending on theradiation dose the person's skin received.

The gastrointestinal manifestation of ARS is referred to asgastrointestinal acute radiation syndrome or GI-ARS. GI-ARS consists ofdiarrhea, dehydration, enterobacterial infection, and in severe cases,septic shock and death (Potten 1990). Following radiation exposure,GI-ARS is thought to be caused by direct damage to stem cells within thebase of the crypts of Ueberkuhn, resulting in mitotic cessation anddeath through apoptotic mechanisms (Potten 1997a, Potten 1997b). Theintegrity of gastrointestinal mucosa depends on a rapid proliferation ofa pool of pluripotent stem cells at the bottom of the crypts (Brittan2002, Gordon 1994, Potten 1997b). Thus, stem cell death is thought to bethe critical element in this process, since surviving intestinal stemcells appear to be sufficient for reconstitution of a crypt-villus unit(Potten 1990). Renewal of the intestinal epithelial barrier depends uponan active stem cell compartment similar to the hematopoietic system.Intestinal crypt-villus precursor clonogen cells are particularlysensitive to ionizing radiation exposure such that with increasingradiation dose, crypt-villus clonogen cells cannot produce enough cellsto repopulate the villi. This results in blunting and diminution invillus height and eventual functional incapacity, leading to decreasednutrient absorption and barrier function, loss of fluid andelectrolytes, and bacterial translocation through the intestinal barrier(Monti 2005, Zhao 2009). Above 8 Gray (Gy), dose-dependent stem celldeath leads to reduction of crypt regeneration, until the level ofregeneration is insufficient to rescue the GI mucosa. From studies inmice, progressive denudation of the epithelium leads, by day 6 to 7after radiation, to death from the GI syndrome. When mitotic activityresumes, precipitous depletion of crypts ensues, presumably as a resultof the onset of reproductive death of crypt clonogens (Withers 1971). Atthe lower-dose range (8-13 Gy), surviving clonogens regenerate the cryptsystem, leading to complete recovery of injured mucosa. At dosesexceeding 14 Gy, massive clonogen loss causes collapse of thecrypt-villus system, mucosal denudation and animal death from thegastrointestinal syndrome (Paris 2001; Potten 1990; Withers 1971;Withers 1969).

The intestinal stem cell compartment is not the only compartmentsensitive to ionizing radiation. Another critical factor involving theresponse of the GI tract to a major physical insult is hypoperfusion ofthe intestine. Persistent gut hypoperfusion is an important incitingevent in the development of the systemic inflammatory response syndromeand multi-organ failure (MOF) (Moore 1999). Increased intestinalvascular permeability together with capillary leakage has been observedin the early period after irradiation (Cockerham 1984; Eddy 1968,Willoughby 1960). Additional post-irradiation alterations includemoderate dilatation and tortuosity of small arterial vessels, reductionin numbers and/or lengths of vessels followed by later occurringhemorrhagic patterns (Eddy 1968). There has been an ongoing controversyconcerning whether the primary lesion after irradiation is intestinalepithelium stem cell death or a result of endothelial cell death (Kirsch2010). Regardless of primary lesion, it is clear that irradiationresults in a complex injury response including death of intestinalepithelial cells, endothelial cells and gut hypoperfusion (Williams2010).

Treatment modalities such as hematopoletic growth factors, i.e.,granulocyte- and/or granulocyte-macrophage colony stimulation factors(G-CSF and G/M-CSF) and erythropoietin (EPO), and hematopoletic stemcell/bone marrow transplantation, are available to attenuate mortalityfrom hematopoletic failure.

The chance of survival for people with ARS decreases with increasingradiation dose. The cause of death within 15 days of radiation exposureis usually damage to the GI tract whereas after 15 days death usually isa consequence of bone marrow injury. For the survivors, the recoveryprocess may last from several weeks up to 2 years (CDC 2013).

There is an urgent need for the development of radiation mitigators, asthere currently are none approved for the treatment of acute radiationsyndrome. RIVPA (SEQ ID NO. 5) has the potential to decrease the acutemortality in ARS, enabling supportive care efforts, and to aid in therecovery of skin damage.

Infection

A variety of microorganisms, including viruses, bacteria, fungi andparasites can cause disease. Microbial cells are distinct from cells ofanimals and plants that are unable to live alone in nature, existingonly as parts of multicellular organisms. Microbial cells can bepathogenic or non-pathogenic, depending, in part, on the microorganismand the status of the host. For example, in an immunocompromised host, anormally harmless bacterium can become a pathogen. Entry into host cellsis critical for the survival of bacterial pathogens that replicate in anintracellular milieu. For organisms that replicate at extracellularsites, significance of bacterial entry into host cells is less welldefined.

Drug resistance remains an obstacle in the ongoing effort to fightinfection. For example, penicillin was effective in treatingStophylococcus aureus until the bacterium became resistant. Throughoutthe second half of the 20^(th) century, new antibiotics, such asvancomycin and methicillin, were developed; these successfully cured S.aureus infection. However, methicillin-resistant strain of S. aureusevolved in the 1970s, and have been plaguing hospitals worldwide eversince. More recently, vancomycin-resistant strains of S. aureus havesurfaced.

With the increasing threat of resistance to antimicrobial drugs and theemergence of new infectious diseases, there exists a continuing need fornovel therapeutic compounds. Therapeutics that act on the host, not thepathogen, are desirable, because they do not encourage pathogenicresistance. In particular, drugs that act on the host via the innateimmune system provide a promising source of therapeutics. There isevidence to indicate that innate responses are instrumental incontrolling most infections, and also contribute to inflammatoryresponses. Inflammatory responses triggered by infection are known to becentral components of disease pathogenesis. An ability to increase hostresistance to infection, while controlling inflammation, would be verybeneficial in the ongoing battle against infection, including infectioncaused by resistant organisms.

IDRs and the Innate Immune System

Innate Defense Regulators (IDRs) interact with intracellular signalingevents and modulate the innate defense response. Whereas much of theinitial work with the IDRs focused on their role in fighting infectionwhile controlling inflammation, recent results in animal models ofchemotherapy- or radiation-induced mucositis and wound healing suggestthat IDRs can be beneficial during the responses to a broader range ofdamage-inducing agents beyond pathogens. IDRs treat and preventinfections by selectively modifying the body's innate defense responseswhen they are activated by PAMPs or DAMPs, without triggering associatedinflammation responses (Matzinger 2002). The same mechanisms underliepositive effects seen in mucositis and wound healing models, wheresignaling downstream of the recognition of DAMPs is affected. RIVPA (SEQID NO. 5) has demonstrated safety in humans and efficacy in animalmodels of fractionated radiation-induced and chemotherapy-induced oralmucositis, in models of chemotherapy induced damage to thegastro-intestinal tract and in models of local and systemicGram-positive and Gram-negative Infection in immunocompetent andimmunocompromised hosts.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1. RIVPA (SEQ ID NO. 5) reduces the duration of severe oralmucositis in a fractionated radiation model.

FIG. 2. RIVPA (SEQ ID NO. 5) reduces the duration of severe oralmucositis in a fractionated radiation model using an optimized dosingregimen.

FIG. 3. RIVPA (SEQ ID NO. 5) reduces the severity of DSS-induced colitisas measured by endoscopy on days 7, 14, and 21 (A) and histopathology onday 21 (B,C,D).

FIG. 4. RIVPA (SEQ ID NO. 5) reduces the duration of severe oralmucositis (A), severity of colitis (B) and body weight loss (C) in achemotherapy model (First study).

FIG. 5. RIVPA (SEQ ID NO. 5) reduces the duration of severe oralmucositis (A), severity of colitis (B) and body weight loss (C) in achemotherapy model (Second study).

FIG. 6. RIVPA (SEQ ID NO. 5) reduces the duration of severe oralmucositis (A), severity of colitis (B) and body weight loss (C) in achemotherapy model in a dose responsive manner.

FIG. 7. Combination of RIVPA (SEQ ID NO. 5) and Vancomycin treatment inan MRSA IP infection model.

FIG. 8. RIVPA (SEQ ID NO. 5) activity in neutropenic mice in the thighabscess MRSA infection model.

FIG. 9. Dose response of RIVPA (SEQ ID NO. 5) in the MRSA bacteremiamodel in immunocompetent mice.

FIG. 10. Dose response of RIVPA (SEQ ID NO. 5) in the MRSA bacteremiamodel in mice lacking T-cells.

FIG. 11. Therapeutic RIVPA (SEQ ID NO. 5) efficacy in the S. aureusacute peritoneal infection model.

FIG. 12. RIVPA (SEQ ID NO. 5) activity in neutropenic mice in the thighabscess S. aureus infection model.

FIG. 13. RIVPA (SEQ ID NO. 5) efficacy in a Klebsiella peritonealinfection model with high (A) and low (B) bacterial infection. * Absenceof a bar in (A) indicates all mice died (0% survival).

FIG. 14. RIVPA (SEQ ID NO. 5) enhances resolution of tissue damage intopically MRSA-infected skin. 48 h Bacterial Burden (A), 96 h Scatterplot (B), Blinded Photographic Scoring at 48 h (C), Blinded PhotographicScoring at 96 h (D). * Absence of a bar in (C) and (D) indicates allmice had a zero score, yielding a mean and standard error of the mean(SEM) of 0±0.

FIG. 15. Lack of RIVPA (SEQ ID NO. 5) on recovery of circulating bloodcell leukocytes (A) or neutrophils (B) after induction of leukopenia inCD-1 mice.

FIG. 16. R(tBg)V1KR(tBg)V2 (SEQ ID NO. 91) reduces the severity of oralmucositis in a chemotherapy model.

FIG. 17. RIV(mp2)A-NH2 (SEQ ID NO. 92) reduces the severity of oralmucositis in a chemotherapy model.

FIG. 18. R(tBg)V1KR(tBg)V2 (SEQ ID NO. 91) enhances survival in an MRSAbacteremia model.

FIG. 19. RIV(mp2)A-NH2 (SEQ ID NO. 92) enhances survival in an MRSAbacteremia model.

DETAILED DESCRIPTION OF THE INVENTION

It is an object of the present invention to provide an isolated peptideconsisting of the amino acid sequence of R(tBg)V1KR(tBg)V2, whereintBg=tert-butyl glycine and further wherein R(tBg)V2 is linked via anamide bond between V1 and K.

It is an object of the present invention to provide An isolated peptideconsisting of the amino acid sequence of RIV(mp2)A-NH2,

wherein mp2=4-Amino-1-methyl-1H-pyrrole-2-carboxylic acid

It is yet another object of the present invention to provide a method oftreating oral mucositis in a subject who has been exposed to a damagingamount of radiation or chemotherapeutic agents, comprising administeringto the patient an effective amount of:

a) a peptide comprising an amino acid sequence of Table 1; or

b) a peptide comprising the amino acid sequence of any of SEQ ID NOs: 5,7, 10, 14, 17, 18, 22, 23, 24, 27, 28, 31, 34, 35, 63, 64, 66-69, 72,76, 77, 90, 91 and 92 or a pharmaceutical salt, ester or amide thereofand a pharmaceutically-acceptable carrier, diluent or excipient.

It is an object of the present invention to provide a method of treatingoral mucositis in a subject who has been exposed to a damaging amount ofradiation or chemotherapeutic agents, comprising administering to thepatient an effective amount of:

a) a peptide comprising an amino acid sequence of up to 7 amino acids,said peptide comprising the amino acid sequence of X₁X₂X₃P (SEQ ID NO:56), wherein:

-   -   X1 is R;    -   X2 is I or V, wherein X2 can be N-methylated;    -   X3 is I or V, wherein X3 can be N-methylated;    -   P is proline or a proline analogue;    -   wherein SEQ ID NO: 56 if the first four amino acids at the        N-terminus of the peptide, or a pharmaceutical salt, ester or        amide thereof and a pharmaceutically-acceptable carrier,        diluent, or excipient; or

b) a peptide comprising the amino acid sequence of any of SEQ ID NOs: 5,7, 10, 14, 17, 18, 22, 23, 24, 27, 28, 31, 34, 35, 63, 64, 66-69, 72,76, 77, 90 and 92 or a pharmaceutical salt, ester or amide thereof and apharmaceutically-acceptable carrier, diluent or excipient.

It is another object of the present invention to provide a method oftreating oral mucositis in a subject who has been exposed to a damagingamount of radiation or chemotherapeutic agents, wherein the peptide isSEQ ID NO: 5 or a pharmaceutical salt, ester, or amide thereof and apharmaceutically-acceptable carrier, diluent, or excipient.

It is another object of the present invention to provide a method oftreating oral mucositis in a subject who has been exposed to a damagingamount of radiation or chemotherapeutic agents, wherein the peptide isadministered orally, parenterally, transdermally, intranasally.

It is yet another object of the present invention to provide a method oftreating oral mucositis in a subject who has been exposed to a damagingamount of radiation or chemotherapeutic agents, wherein the effectiveamount of peptide administered to a subject is at least 1 mg/kg. In apreferred embodiment the effect amount of peptide administered to asubject is about 1.5 mg/kg to 6 mg/kg.

It is yet another object of the present invention to provide a method oftreating oral mucositis in a subject who has been exposed to a damagingamount of radiation or chemotherapeutic agents, wherein the peptide isadministered to the subject every third day during radiation orchemotherapeutic agent administration.

It is still another object of the present invention to provide a methodof treating oral mucositis in a subject who has been exposed to adamaging amount of radiation or chemotherapeutic agents, wherein thepeptide is administered in combination with an oral dosage form of atopically active corticosteroid or a metabolite thereof to the subject,wherein the oral dosage form is effective for topical or local treatmentof the gastrointestinal tract and oral cavity of the subject and furtherwherein the subject exhibits symptoms of inflammation due to tissuedamage arising from radiation or chemotherapy treatment. Representativetopically active corticosteroids include, but are not limited to,beclomethasone 17,21-dipropionate, aclomethasone dipropionate,budesonide, 22S budesonide, 22R budesonide,beclomethasone-17-monopropionate, clobetasol propionate, diflorasonediacetate, flunisolide, flurandrenolide, fluticasone propionate,halobetasol propionate, halcinodde, mometasone furoate, andtriamcinolone acetonide. In a preferred embodiment of this invention,the topically active corticosteroid is beclomethasone dipropionate. Theeffective amount of topically active corticosteroid in each dosage formmay vary from patient to patient, and may be readily determined by oneskilled in the art by well-known does-response studies. Such effectiveamounts will generally range between about 0.1 mg/day to about 8 mg/day,and more typically range from about 2 mg/day to about 4 mg/day.

It is still another object of the present invention to provide a methodmitigating the gastrointestinal, hematopoletic and cutaneous impacts ofacute radiation syndrome in a subject who has received a high,penetrating dose of radiation to a substantial portion of their body ina short period of time.

It is still another object of the present invention to provide a methodof treating acute radiation syndrome in a subject who has received ahigh, penetrating dose of radiation to a substantial portion of theirbody in a short period of time, wherein the peptide is administered incombination with an oral dosage form of a topically activecorticosteroid or a metabolite thereof to the subject, wherein the oraldosage form is effective for topical or local treatment of thegastrointestinal tract and oral cavity of the subject and furtherwherein the subject exhibits symptoms of inflammation due to tissuedamage arising from radiation or chemotherapy treatment. Representativetopically active corticosteroids include, but are not limited to,bedomethasone 17,21-dipropionate, aclomethasone dipropionate,budesonide, 22S budesonide, 22R budesonide,beclomethasone-17-monopropionate, clobetasol propionate, diflorasonediacetate, flunisolide, flurandrenolide, fluticasone propionate,halobetasol propionate, halcinonide, mometasone furoate, andtriamcinolone acetonide. In a preferred embodiment of this invention,the topically active corticosteroid is bedomethasone dipropionate. Theeffective amount of topically active corticosteroid in each dosage formmay vary from patient to patient, and may be readily determined by oneskilled in the art by well-known does-response studies. Such effectiveamounts will generally range between about 0.1 mg/day to about 8 mg/day,and more typically range from about 2 mg/day to about 4 mg/day.

It is still another object of the present invention to provide a methodof treating and/or preventing Infection (e.g., a microbial infection) ina subject, by administering to the subject a peptide having orcomprising the amino acid sequence of TABLE 1 or an analogue,derivative, or variant thereof or obvious chemical equivalent thereof.By way of example, the subject may have, or be at risk of having,infection. In one embodiment, the peptide modulates innate immunity inthe subject, thereby treating and/or preventing the infection in thesubject.

Exemplary Infections which may be treated and/or prevented by the methodof the present invention include an infection by a bacterium (e.g., aGram-positive or Gram-negative bacterium), an infection by a fungus, aninfection by a parasite, and an infection by a virus. In one embodimentof the present invention, the infection is a bacterial Infection (e.g.,Infection by E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa,Salmonella spp., Staphylococcus aureus, Streptococcus spp., orvancomycin-resistant enterococcus). In another embodiment, the infectionis a fungal infection (e.g., infection by a mould, a yeast, or a higherfungus). In still another embodiment, the Infection is a parasiticinfection (e.g., infection by a single-celled or multicellular parasite,including Giardia duodenalis, Cryptosporidium parvum, Cyclosporacayetanensis, and Toxoplasma gondii). In yet another embodiment, theinfection is a viral infection (e.g., infection by a virus associatedwith AIDS, avian flu, chickenpox, cold sores, common cold,gastroenteritis, glandular fever, influenza, measles, mumps,pharyngitis, pneumonia, rubella, SARS, and lower or upper respiratorytract infection (e.g., respiratory syncytial virus)). Formulation of theDosage Form

The dosage form of RIVPA (SEQ ID NO. 5) is an aqueous, asepticallyprocessed, sterile solution for injection. Each vial contains 5 mL of a60 mg/mL solution (300 mg of RIVPA (SEQ ID NO. 5)). RIVPA (SEQ ID NO. 5)is formulated in Water for Injection and pH adjusted to a target valueof 6.0. The formulation contains no excipients and has an osmolality of^(˜)300 mOsm/kg.

Route of Administration

RIVPA (SEQ ID NO. 5) drug product will be diluted in sterile saline tothe appropriate concentration for injection, determined on a mg/kg basisby the recipient's weight and the designated dose level. Diluted RIVPA(SEQ ID NO. 5) will be administered as an intravenous (IV) infusion in25 mL over 4 minutes, once every third day.

EXAMPLES Peptide Synthesis

The peptides in Table 1 were synthesized using a solid phase peptidesynthesis technique.

All the required Fmoc-protected amino acids were weighed in three-foldmolar excess relative to the 1 mmole of peptide desired. The amino acidswere then dissolved in Dimethylformaide (DMF) (7.5 ml) to make a 3 mMolsolution. The appropriate amount of Rink amide MBHA resin was weighedtaking in to account the resin's substitution. The resin was thentransferred into the automated synthesizer reaction vessel and waspre-soaked with Dichloromethane (DCM) for 15 minutes.

The resin was de-protected by adding 25% piperidine in DMF (30 ml) tothe resin and mixing for 20 minutes. After de-protection of the resinthe first coupling was made by mixing the 3 mMol amino acid solutionwith 4 mMol 2-(1H-benzitriazole-1-yl)-1,1,3,3-tetramethyluroniumhexafluorophosphate (HBTU) and 8 mMol N,N-diisopropylethylamine (DIEPA).The solution was allowed to pre-activate for 5 minutes before beingadded to the resin. The amino acid was allowed to couple for 45 minutes.

After coupling the resin was thoroughly rinsed with DMF andDimethylacetamide (DMA). The attached Fmoc protected amino acid wasdeprotected in the same manner described above and the next amino acidwas attached using the same coupling scheme AA:HBTU:DIEPA.

After the completion of the synthesis the peptide was cleaved from theresin with the use of a cleavage cocktail containing 97.5%Trifluoroacetic acid (TFA) and 2.5% water. The resin was allowed to swimin the cleavage cocktail for 1½ hours. The solution was then filtered bygravity using a Buchner funnel and the filtrate was collected in a 50 mlcentrifugation tube. The peptide was isolated by precipitating withchilled diethyl ether. After centrifuging and decanting diethyl etherthe crude peptide was washed with diethyl ether once more before beingdried in a vacuum desiccator for 2 hours. The peptide was then dissolvedin de-ionized water (10 ml), frozen at −80° C. and lyophilized. The drypeptide was then ready for HPLC purification. Due to the hydrophilicnature of these peptides the diethyl ether peptide isolation did notwork. Therefore a chloroform extraction was required. The TFA wasevaporated and the resulting peptide residue was dissolved in 10% aceticacid (15 ml). The Impurities and scavengers were removed from the aceticacid peptide solution by washing the solution twice with chloroform (30ml). The aqueous peptide solution was then frozen at −80° C. andlyophilized resulting in a powdered peptide ready for HPLC purification.

Peptides +RIxVPA (SEQ ID NO. 33) and +RIVPAx (SEQ ID NO. 34) eachcontained one N-methyl amino acid. This coupling was carried out bycombining the N-methyl amino acid, PyBroP and N-hydroxybenzotriazole*H2O(HOBt) and DIEPA solutions together in the RV containing the resin.After allowing to couple for 45 minutes the N-methyl amino acid was thendoubled coupled to ensure complete coupling. It was observed that thecoupling following the N-methyl amino acid was not fully complete.Therefore this coupling was performed usingN,N,N′,N′-Tetramethyl-O-(7-azabenzotriazol-1-yl)uroniumhexafluorophosphate (HATU) instead of HBTU. This still resulted in acrude peptide that typically contained two impurities totaling 30-40% ofthe total purity. The peptide was purified under modified HPLCconditions to isolate the pure peptide peak away from the closelyeluting impurities.

R(tBg)V1KR(tBg)V2 (SEQ ID NO. 91) is an 8-residue peptide dendrimer withsymmetrical branches occurring off of a fourth amino acid lysine thatpossesses two functional amine groups. The peptide has been synthesizedwith solid-phase peptide synthesis techniques, utilizing a di-Fmocprotected fourth amino acid to facilitate the coupling of the branches,using the general synthesis techniques described above.

In addition, these peptides can also be synthesized with solution phasepeptide synthesis techniques (Tsuda et al. 2010) and commonly known toexperts in the art.

Efficacy in Oral Mucositis

RIVPA (SEQ ID NO. 5) and other IDRs modulate the innate defense responseto tissue injury, reducing the severity of damage caused by theinflammatory cascade and enhancing resolution of disease. This attributeof IDRs has been demonstrated in chemotherapy-induced oral and GImucositis in mice, in radiation-induced oral mucositis in hamsters andin DSS-induced colitis in mice. In each of these models, the Initialdamage is thought to trigger a cascade of innate defense signaling whichincreases the severity of the injury (Marks 2011; Sonis 2010). RIVPA(SEQ ID NO. 5) and other IDRs offset the signaling cascade, reducing theresultant severity of the injury and reducing the duration of severetissue damage.

The optimum dosing regimen for RIVPA (SEQ ID NO. 5) and other IDRsidentified in the MRSA bacteremia model has been further confirmed ininjury models, where the longer duration of disease makes repeat dosingmore informative. Dosing of 25 mg/kg every third day was found to beoptimal, reflecting the durable pharmacodynamic impact of RIVPA andother IDRs (SEQ ID NO. 5) despite its rapid PK clearance (withinminutes) from the circulation of mice.

RIVPA (SEQ ID NO. 5) significantly reduced the severity and duration ofmucositis in a model of radiation-induced oral mucositis in hamsters,particularly when administered every third day during the fractionatedradiation therapy. These studies confirmed that optimal dosing of RIVPA(SEQ ID NO. 5) involves dosing every third day and that the 25 mg/kgdose level is effective. In this model, cannulated male Golden Syrianhamsters were treated with 7.5 Gy of radiation, directed at the evertedleft cheek pouch, on Days 0, 1, 2, 3, 6, 7, 8 and 9. Mucositis wasevaluated every second day between Days 7 and 35, with peak mucositisseverity generally occurring around Day 19. In the first study, RIVPA(SEQ ID NO. 5) (25 mg/kg IV) was administered either every third daystarting on Day 0 and continuing until Day 33 (Q3d d0-33), or on days ofradiation therapy (Days 0, 1, 2, 3, 4, 7, 8, 9) or every third daystarting on Day 6 and continuing to Day 24 (Q3d d6-24). On days whereboth RIVPA (SEQ ID NO. 5) and radiation was administered, RIVPA (SEQ IDNO. 5) was given 2 hours after radiation. The results of this study areshown in FIG. 1. RIVPA (SEQ ID NO. 5) treatment was most effective whenadministered every third day throughout the period or on days ofradiation, whereas treatment starting 6 days after initiation ofradiation was not beneficial (i.e., Q3d d6-24). A follow-up study wasundertaken to evaluate dosing with 25 mg/kg IV RIVPA (SEQ ID NO. 5) Q3dd0-33, on days of radiation, or every third day during radiationtreatment (i.e., Days 0, 3, 6 and 9). The results of this study areshown in FIG. 2. Treatment every third day during radiation was found tobe optimal, likely reflecting the durability of the RIVPA (SEQ ID NO. 5)pharmacodynamic effect, coupled with the reduction of injection stresscaused by fewer IV injections in these small rodents.

RIVPA (SEQ ID NO. 5) has also shown efficacy in mouse models ofchemotherapy-induced oral and gastrointestinal mucositis, consistentwith the response of the innate immune response to chemotherapy and/orradiation damage. In these studies, RIVPA (SEQ ID NO. 5) administrationwas associated with a statistically significant reduction in theduration of severe oral mucositis in a model of chemotherapy-inducedmucositis in the mouse. A trend towards reduced colitis was alsoobserved, although the mild GI damage in the control group rendered theresult not statistically significant. In each study, 5-fluorouracil (60mg/kg IP) was administered to male C3H/HeN mice on Days −4 and −2. OnDay 0, a chemical burn was applied to the underside of the mouse tongue,inducing mucositis which generally peaked on Day 2. Mouse tongues werescored for mucositis daily from Days 1 to 14, with scores 23representing severe mucositis. Body weights were also measured daily andcolitis severity was determined by video endoscopy on Days 4 and 7. Inthe first study, RIVPA (SEQ ID NO. 5) (25 mg/kg IV) was administeredeither once on Day −4 immediately prior to chemotherapy, twice on Days−4 and −2 immediately after chemotherapy or 3 times on Days −1, 2 and 5.RIVPA (SEQ ID NO. 5) administration on multiple occasions throughout theperiod of peak mucositis damage was the most effective (i.e., on Days−1, 2 and 5). The results of this study are shown in FIG. 4. In thesecond study, RIVPA (SEQ ID NO. 5) (25 mg/kg IV) was administered oneither Days −1, 2 and 5, Days −1, 1 and 3 or Days 0, 2, and 4. Theresults of this study are shown in FIG. 5. Statistically significantchanges in the duration of severe mucositis (FIG. 5—panel A), theseverity of colitis on Day 4 (FIG. 5—panel B) and the mean body weightloss (FIG. 5—panel C) correlated among the groups. In the third study,RIVPA (SEQ ID NO. 5) (25 or 5 mg/kg IV, as indicated) was administeredeither on Days −1, 2 and 5 or on Days 1 and 3. Again, the dosing regimenutilizing RIVPA (SEQ ID NO. 5) on every third day was most effective,with decreased dose levels resulting in decreased efficacy. Themucositis, colitis and body weight results from this study are shown inFIG. 6 as A, B, and C, respectively. Statistical significance wasassessed for oral mucositis using a chi-square analysis and for bodyweight area under the curve (AUC) with an ANOVA on ranks.R(tBg)V1KR(tBg)V2 (SEQ ID NO. 91) and 92 also demonstrated efficacy inthe mouse model of chemotherapy-induced mucositis, where the mucositisscores were evaluated for 4 days after induction of mucositis (FIG. 16,FIG. 17). Treatment with R(tBg)V1KR(tBg)V2 (SEQ ID NO. 91) andRIV(mp2)A-NH2 (SEQ ID NO. 92) was administered on Days −1 and 2 at adose of 25 mg/kg IV.

Efficacy in Response to Radiation Damage

RIVPA (SEQ ID NO. 5) and other IDRs modulate the innate defense responseto tissue injury, reducing the severity of damage caused by theinflammatory cascade and enhancing resolution of disease. As describedabove, IDRs can mitigate the response to radiation damage in an oralmucositis model (FIG. 1, FIG. 2). In another model, assessing theprevention of radiation-induced mucositis (25 Gy administered to themouse snout on Day 0), RIVPA (SEQ ID NO. 5) (5 doses of 25 mg/kgadministered IV every second day) did not have any significant impact ondisease progression. Progressive thinning of the mouse tongue wasassessed on Days 0, 2, 4, 6, 8, and 10 by histopathological analysis ofthe number of basal and suprabasal apoptotic, mitotic and totalepithelial cells per unit area and per unit length. It is noted that thedose of radiation used (25 Gy) was chosen such that progressive thinningof the tongue epithelium was observed but no overt mucositis occurred.This result demonstrates the lack of proliferative potential of RIVPA(SEQ ID NO. 5), and suggests that RIVPA (SEQ ID NO. 5) effects are onlyobservable once the relevant pathways are stimulated by overt tissuedamage or pathogen invasion.

Efficacy in the Gastrointestinal Tract

The ability of IV RIVPA (SEQ ID NO. 5), administered pre-emptively ortherapeutically, to directly protect GI mucosal surfaces was confirmedin a DSS-induced colitis model. In this model, DSS was administered as a3% DSS solution in the drinking water of male C57BL/6 mice from Days 0to 5 of the study. Colitis was monitored by video endoscopy on Days 7,14 and 21. RIVPA (SEQ ID NO. 5) (25 mg/kg IV) was administered everythird day from Days 0 to 18 (Q3d d0-18), from Days 3 to 18 (Q3d d3-18)or from Days 6 to 18 (Q3d d6-18). The results of the study are shown inFIG. 3. By Day 14, all RIVPA (SEQ ID NO. 5) treatment regimensdemonstrated a statistically significant reduction in endoscopic colitisseverity score. However, reduction in Day 7 scores was only observed ingroups which had received at least 2 doses of RIVPA (SEQ ID NO. 5) bythat time (i.e., Q3d d0-18 and Q3d d3-18 but not Q3d d6-18). On Day 21,all 3 treatment groups appeared to be responding in a similar manner.Histopathology of the colon on Day 21 indicated that some RIVPA (SEQ IDNO. 5) treated groups had statistically significantly decreased edemaand necrosis, whereas other RIVPA (SEQ ID NO. 5) treated groups hadsimilar responses which did not reach statistical significance.Statistical analysis was undertaken using t-tests and an asteriskindicates statistically significant differences from control (p<0.05).

As described above, IDRs are also able to reduce the duration and/orseverity of gastrointestinal mucositis in a chemotherapy-inducedmucositis model (FIG. 4, FIG. 5, FIG. 6).

Efficacy in Infected Animals

RIVPA (SEQ ID NO. 5) reduces bacterial burden and improves survival inthe presence or absence of antibiotic treatment in various murineinfection models, with consistent efficacy at dose levels of 25 mg/kg IVand higher and with an enduring pharmacodynamic effect of up to 5 days.RIVPA (SEQ ID NO. 5) efficacy is complementary to antibiotic treatmentin both normal and immune compromised mice. Efficacy of RIVPA (SEQ IDNO. 5) has been demonstrated against disease caused by Gram-positive (S.aureus and MRSA) and Gram-negative (Klebsiella, E. coli and B.pseudomollei) Infections.

S. aureus

RIVPA (SEQ ID NO. 5) has been tested both in combination with vancomycintreatment and as a stand-alone treatment.

RIVPA (SEQ ID NO. 5) treatment increased survival in a MRSA peritonealinfection model when administered in combination with a sub-optimalantibiotic dose of vancomycin (Study #: D-7-E-11). RIVPA (SEQ ID NO. 5)(50 mg/kg) or saline treatment was administered IV either 48 or 72 hprior to inoculation with MRSA (UC6685; 8.2×10⁷ colony forming units[cfu]) to female CF-1 mice (N=10/group). Vancomycin treatment (3 mg/kg)was administered subcutaneously (SC), 1 and 5 h after infection.Survival was monitored once daily for 5 days. The results of this studyare shown in FIG. 7.

RIVPA (SEQ ID NO. 5) is also effective when administered by itself.Multiple studies with IV administered RIVPA (SEQ ID NO. 5) wereconducted in a MRSA bacteremia model. RIVPA (SEQ ID NO. 5)administration demonstrated a dose response in this model in eitherimmunocompetent Balb/c mice or nu/nu mice lacking T-cells, with a singledose of 50 mg/kg resulting in statistically significant enhancedsurvival over the saline control. In the first study, MRSA (USA300, 7.3log 10 cfu) was administered via IV injection into the tail vein offemale Balb/c mice at time 0. Four hours prior to infection, a singledose of saline or RIVPA (SEQ ID NO. 5) at the indicated dose levels wasinjected IV into the tail vein. Sub-optimal antibiotic treatment(linezolid, 6.25 mg/kg) was administered once orally immediately afterinfection. Survival was monitored for 21 days after the infection. Theresults of this study are shown in FIG. 9. In the second study, RIVPA(SEQ ID NO. 5) (IV) or saline (IV) was administered once 4 h prior toinfection with MRSA (strain USA300, 7.0 log₁₀ cfu) via the tail veininto female nu/nu mice. Survival was monitored for 14 days, as shown inFIG. 10. Statistically significant differences (i.e., p≦0.05) insurvival were found with the 50 mg/kg dose level as assessed usingKaplan Meier analysis of each treatment group relative to the salinecontrol.

In summary, investigations using stand-alone IV RIVPA (SEQ ID NO. 5)treatment in various S. aureus infection studies have demonstrated that:

-   -   The effects of RIVPA (SEQ ID NO. 5) are dose dependent between 1        and 50 mg/kg in mouse, with dose levels of 25 mg/kg and higher        consistently demonstrating efficacy (Table 2; FIG. 9 and FIG.        10). This dose level was also effective in the more chronic        disease context available in injury models (FIG. 1 to FIG. 6).

TABLE 2 Rate of Successful Treatment of S. aureus Infection with aSingle IV RIVPA (SEQ ID NO. 5) Treatment as a Function of Dose Level %Successful Treatments RIVPA RIVPA (SEQ ID NO. 5) (SEQ ID NO. 5) %Successful Treatments^((i)) administered 4 h prior Dose Level Any DoseSchedule to infection (mg/kg) (# tested groups) (# studies) 50^((ii))100 (N = 4)  100 (N = 2)  25^((iii)) 67 (N = 6)  50 (N = 4)  5^((iv)) 42(N = 12) 33 (N = 6)  1^((v)) 0 (N = 2)  0 (N = 2) ^((i))Successfultreatments demonstrated at least a 20% increase in survival over therelevant saline control. ^((ii))Study #: TPS-8-B-100, TPS-8-B-150,TPS-8-B-116, D-7-E-9 ^((iii))Study #: TPS-8-B-100, TPS-8-B-150,TPS-8-B-120, TPS-8-B-112 ^((iv))Study #: TPS-8-B-100, TPS-8-B-150,TPS-8-B-116, TPS-8-B-114, TPS-8-B-120, TPS-8-B-101 ^((v))Study #:TPS-8-B-100, TPS-8-B-150

-   -   Daily dosing of RIVPA (SEQ ID NO. 5) is not required and dosing        every 2^(nd) or 3^(rd) day is sufficient in the more chronic        disease context available in Injury models, it was further        confirmed that dosing every 3^(rd) day appears to be optimal        (data not shown).    -   RIVPA (SEQ ID NO. 5) can be administered up to 24 h after the        initiation of Infection in the MRSA bacteremia model and still        confer a survival benefit (data not shown). Hence its action is        rapid.    -   Depending on dose level, a single dose of RIVPA (SEQ ID NO. 5)        can be administered up to 5 days prior to the initiation of        infection and still confer a survival benefit (data not shown),        reflecting the durable pharmacodynamic impact of RIVPA (SEQ ID        NO. 5) despite its rapid pharmacokinetic (PK) clearance (within        minutes) from the circulation of mice.    -   The survival benefit conferred by RIVPA (SEQ ID NO. 5) treatment        can be sustained for at least 21 days (FIG. 9).

RIVPAY* (SEQ ID NO. 90) and R(tBg)V1KR(tBg)V2 (SEQ ID NO. 91) (5 mg/kgadministered 4 hours prior to infection) also improve survival in anMRSA bacteremia model (FIG. 18; FIG. 19).

Local administration of RIVPA (SEQ ID NO. 5) has also been demonstratedto be effective when the administration is local to the site ofinfection. In a Gram-positive peritoneal infection model in mouse, RIVPA(SEQ ID NO. 5) significantly reduced the bacterial load by over 7 logs(Study #: D-7-E-14). Intraperitoneal (IP) injection of S. aureus(Catalog No. 25923, ATCC, 6×10′ cfu) with 5% mucin was administered IPto female CD-1 mice (N=8/group) and RIVPA (SEQ ID NO. 5) (9.5 mg/kg) wasinjected IP 4 h later. Mice were sacrificed 24 h after infection andperitoneal lavage fluid was assessed for bacterial counts. The resultsof this study are shown in FIG. 11 (each data point represents theresult from an individual mouse—dead mice were given the highestbacterial count of any mouse obtained in the study and are representedas open symbols in the graph).

RIVPA (SEQ ID NO. 5) also significantly reduced bacterial load inneutropenic mice in an S. aureus thigh abscess infection model whenadministered as a local intramuscular (IM) injection. Female Swissalbino mice (N=8/group) were rendered neutropenic by treatment with Cp(100 mg/kg), 3 and 1 days before IM infection with S. aureus (CatalogNo. 29213, ATCC, ^(˜)9.5×10⁵ cfu). RIVPA (SEQ ID NO. 5) (50 mg/kg) wasadministered IM 24 h prior to infection and vancomycin (100 mg/kg) wasadministered SC at 1, 6 and 18 h after infection. The number ofbacterial cfu present in the infected thigh was assessed 24 h afterInitiation of infection in each group. The results of this study areshown in FIG. 12.

Klebsiella

RIVPA (SEQ ID NO. 5) increased survival in a Gram-negative peritonealinfection model when administered either locally (IP) or systemically(IV). Of note, systemic administration appeared as good or better thanlocal administration. RIVPA (SEQ ID NO. 5) treatment (24 mg/kg) wasadministered either IP (24 h prior to infection or 4 h post-infection)or IV (4 h post-infection) to female Balb/c mice (N=8/group) inoculatedwith Klebsiella pneumoniae (Catalog No. 43816, ATCC) at either 2.8×10⁵cfu (FIG. 13—panel A) or 5.3×10² cfu (FIG. 13—panel B) and survival wasmonitored over 24 h. The protective effects of RIVPA (SEQ ID NO. 5) inthis context are shown in FIG. 13. A survival endpoint is shown foranimals receiving the higher inoculum of bacteria (panel A). All animalsreceiving the lower inoculum survived in all groups (panel B) and wereassessed for clinical signs (e.g., piloerection, decreased movement,hunched abdomen, etc.) 24 h after infection; these are summarized asclinical scores.

Efficacy in Skin Damage

Systemically administered RIVPA (SEQ ID NO. 5) is also efficacious inthe case of skin injury and infection, accelerating skin healing in anMRSA skin infection model. Infection was initiated 1 day after the hairwas removed from the dorsal area of each mouse. RIVPA (SEQ ID NO. 5) (25mg/kg IV or 100 mg/kg SC) was administered 4 h prior to infection and atvarious times after infection as indicated. Oral linezolid was used asthe comparator and was administered daily at 12.5 mg/kg. On Day 0 (at −1h) each mouse was anesthetized using isoflurane and the shaved dorsalskin was damaged by 7 consecutive applications and removals of surgicaltape. This lesion was then immediately infected by topicaladministration of 10 μL of the bacterial suspension, delivering a totalchallenge of 7.6 log₁₀ cfu per mouse. Efficacy was evaluated bymeasurement of the bacterial burden in punch biopsies of the skin at 48h (FIG. 14—panel A) and 96 h (FIG. 14—panel B) following the bacterialchallenge and by macroscopic assessment of digital images of the skin bya blinded, board-certified pathologist at 48 h (FIG. 14—panel C) and 96h (FIG. 14—panel D) after infection. Of note, neither linezolid norRIVPA (SEQ ID NO. 5) reduced bacterial load in the biopsies at 48 or 96h relative to control, although the localization of any of the isolatedbacteria (i.e., on the skin surface or within the tissue) was notdetermined. Nevertheless, wound healing clearly occurred. The meanbacterial burden for each therapeutic group was statistically comparedto that of its time-matched saline control through use of a t-testcomparison of means, assuming unequal variances, performed on Excel.Comparisons which returned a p value ≦0.05 were considered statisticallydifferent.

Safety Pharmacology in Healthy Animals:

Two pilot and 2 definitive repeat-dose toxicity studies were conductedwith RIVPA (SEQ ID NO. 5) in mice and cynomolgus monkeys using theintravenous (IV; slow bolus) route of administration. All studies wereconducted by LAB Research Inc., Canada.

Non-GLP pilot toxicology studies indicated that the maximum tolerateddose (MTD) of a single administration of RIVPA (SEQ ID NO. 5),administered as an IV injection over 30 to 60 seconds, is 88 mg/kg(actual dose) in mouse. In non-GLP pilot studies in nonhuman primates(NHP), mild clinical signs (shallow/labored respiration, decreasedactivity, partially dosed eyes and muscle twitches) were noted in 1 orboth animals after administration of 90 (1 animals), 180 (both animals)and 220 (1 animal) mg/kg RIVPA (SEQ ID NO. 5) during and shortly afterdosing. These resolved within a few minutes without detectable residualeffects.

The safety of multiple daily injections of RIVPA (SEQ ID NO. 5) has alsobeen evaluated in GLP studies in mice and cynomolgus monkeys. In mouse,doses of 20, 60, or 90 mg/kg/day were given IV for 14 days. Deaths wereobserved at the high dose, preceded mainly by labored respiration andrecumbancy. Lethality was also observed in 1 animal given 60 mg/kg butno other animals exhibited clinical signs at this dose. No testarticle-related mortality or clinical signs were observed at 20 mg/kg.In survivors of all groups, there was no evidence of toxicity in anyorgan or abnormal biochemistry or hematology. No adverse effects wereobserved at 20 mg/kg for 14 days.

RIVPA (SEQ ID NO. 5) at 20, 80, 160 mg/kg/day was given IV to cynomolgusmonkeys for 14 days. Transient decreased activity and partially closedeyes continued to be observed during and shortly after dosing at 160mg/kg for the first 3 days in most animals, then sporadically throughoutthe remaining dosing period. In all cases, these clinical signs resolvedwithin a few minutes. No adverse effects were observed on any othermeasured parameter or microscopically in any tissue. The administrationof RIVPA (SEQ ID NO. 5) at doses of 20 and 80 mg/kg/day did not resultin any evidence of toxicity. A dose level of 80 mg/kg/day was consideredto be the No-Observed-Adverse-Effect-Level (NOAEL) for this study.

No effects of RIVPA (SEQ ID NO. 5) have been observed on the centralnervous system (CNS) in any study at any dose level and little or noradiolabelled RIVPA (SEQ ID NO. 5) was found in the mouse CNS at doselevels of either 20 or 90 mg/kg. No interaction was detected betweenRIVPA (SEQ ID NO. 5) and a battery of CNS receptors and ion channels invitro.

A cardiovascular (CV)/pulmonary study in cynomolgus monkey using singleIV doses of 20 or 80 mg/kg revealed no cardiovascular effects or changesin electrocardiogram (ECG) parameters. No respiratory effects wereobserved at doses of 20 or 80 mg/kg. At a dose of 80 mg/kg in thisstudy, RIVPA (SEQ ID NO. 5) was associated with transient drooping eyelids and prostration during dosing. At 220 mg/kg, the administration ofRIVPA (SEQ ID NO. 5) was associated with transient, severe clinicalsigns such as drooping eye lids, tremor, prostration, paleness,convulsion and collapse. In 1 animal, the high dose caused a markedreduction in respiratory rate followed by bradycardia, hypotension anddeath.

Overall, the NOAEL is considered to be 80 mg/kg/day for cynomolgusmonkeys since transient clinical signs were limited to a single studyand occurred in only 2 instances of the 98 administrations of the drugat this dose level.

No carcinogenicity, mutagenicity or reproductive toxicity studies havebeen conducted with RIVPA (SEQ ID NO. 5).

The effect of RIVPA (SEQ ID NO. 5) on the Innate defense system ishighly selective. Consistent with these findings, no changes wereobserved in immune-related organ weights, histopathology, hematology andclinical chemistry during mouse and NHP 14-day toxicity studies. In thelatter study, no effect on T-cell, B-cell or NK-cell counts was observedafter 14 days of intravenous RIVPA (SEQ ID NO. 5) dosing in the NHP.RIVPA (SEQ ID NO. 5) did not promote the proliferation of either mouseor human normal blood cells in vitro, nor of primary human leukemiacells in vitro. Collectively, there is no indication of a potential forRIVPA (SEQ ID NO. 5) to cause immunotoxicity or non-specific immuneactivation. No hyperactivation or suppression of adaptive immuneresponses, or other impact on the phenotypes of cells associated withadaptive immunity, has been detected following RIVPA (SEQ ID NO. 5)administration.

In summary, the major toxicological finding was an acute-onsetrespiratory depression, accompanied by labored breathing, recumbency andtransient decreased activity. At its most severe, the acute toxicityresulted in death. Clinical signs were all reversible when dosing wasdiscontinued and animals were observed to recover within minutes, withno subsequent adverse sequellae of clinical symptoms or toxicologicalfindings. A cardiovascular/pulmonary safety pharmacology study innonhuman primates confirmed no cardiac toxicity or QT prolongation wasoccurring.

The observed respiratory depression occurred at different dose levels indifferent species, and was not predicted by allometric scaling. Inparticular, the mouse appeared to be the most sensitive species withacute toxicity occurring rarely at 60 mg/kg (HED: ^(˜)5 mg/kg) andcommonly at 90 mg/kg (HED: ^(˜)7 mg/kg). In contrast in NHP (cynomologusmonkey), acute toxicity occurred occasionally at 160 mg/kg (HED: ^(˜)50mg/kg) and consistently at 240 mg/kg (HED: ^(˜)78 mg/kg). Furtherstudies with RIVPA (SEQ ID NO. 5) analogs in acute mouse toxicitystudies have indicated that the toxicity is related to the charge butnot the specific structure (amino acid sequence) or target proteinbinding status of the molecule, suggesting that the acute toxicity isdue to a high instantaneous concentration of a charged molecule thatscales with blood volume as opposed to allometrically. Moreover,mechanistic studies in mice have indicated that the respiratorydepression is due to altered activity of the phrenic nerve.

Safety Pharmacology for Leukopenia and/or Infection:

In a non-GLP pharmacology study, RIVPA (SEQ ID NO. 5) did not alter therecovery of circulating blood cell populations after the induction ofleukopenia in CD-1 mice. Leukopenia was induced with 2 IP injections ofCp (150 mg/kg on Day 1 and 100 mg/kg on Day 4), resulting inwell-established leukopenia by Day 4 that persisted until approximatelyDay 10. Saline or RIVPA (SEQ ID NO. 5) (20 or 50 mg/kg) was administeredIV on Days 5, 7, 9 and 11. Six animals per group were sacrificed on eachof Days 6, 8, 10, 12 and 14 and evaluated for complete blood count anddifferential. Neither the levels nor dynamics of the total leukocyte anddifferential white blood cell counts were altered during the course ofrecovery when compared to the vehicle control group (FIG. 15).

Infection studies in leukopenic animals have revealed no interference ofRIVPA (SEQ ID NO. 5) with antibiotic efficacy.

The lack of RIVPA (SEQ ID NO. 5) processing by, or inhibition of, CYP450enzymes, the primary metabolism of RIVPA (SEQ ID NO. 5) by proteasesthroughout body tissues and the very minor role played by urine, fecesand bile excretion in RIVPA (SEQ ID NO. 5) clearance suggests thatpharmacokinetic drug-drug interactions will be minimal.

iv. Clinical Experience

Clinical experience with RIVPA (SEQ ID NO. 5) was obtained in a Phase 1Study. The primary objective of the study was to determine the maximumtolerated dose (MTD) of single and repeat ascending doses of RIVPA (SEQID NO. 5) injectable solution following IV administration in healthyvolunteers. The secondary objectives of this study included theassessment of the dose limiting toxicity (DLT), safety, PK andpharmacodynamic (PD) profiles of RIVPA (SEQ ID NO. 5) after single andrepeated ascending IV doses of RIVPA (SEQ ID NO. 5). The study wasdivided into 2 phases: a single-ascending dose (SAD) phase and amultiple-ascending dose (MAD) phase.

Human Safety

Single IV doses of RIVPA (SEQ ID NO. 5) were well tolerated up to themaximum tested (8 mg/kg) and daily IV doses were well tolerated up tothe maximum tested (6.5 mg/kg for 7 days). There were no dose limitingtoxicities (DLTs) and the MTD was not reached in either phase of thetrial. There were no deaths and no clinically significant, severe, orserious Adverse Events (AEs) reported during the study. No safetyconcerns or significant differences in mean values or changes frombaseline were observed for vital sign measurements, clinical laboratoryor electrocardiogram (ECG) results between drug-treated and placebocontrol subjects.

Single Ascending Dose Phase:

The incidence of TEAEs for those subjects who received RIVPA (SEQ ID NO.5) was not dose-related and events did not occur at a clinicallysignificant higher rate for subjects who received RIVPA (SEQ ID NO. 5)compared to those who received placebo. The most frequently reportedTEAEs (observed in more than one subject who received RIVPA (SEQ ID NO.5) and in a higher proportion (%) than placebo subjects) were studytreatment procedure-related events (General Disorders and AdministrationSite Conditions) such as vessel puncture site haematoma, vessel puncturesite reaction and vessel puncture site pain. All vessel puncture-relatedevents were mild and determined to be unrelated to study treatment bythe QI. The second most frequently reported TEAEs were Nervous SystemDisorders, specifically headache and dizziness; these events were onlymild to moderate. All other TEAEs were reported by only 1 subject at anygiven dose level (maximum of 3 dose levels). No clinically significanttrends in the nature or duration of TEAEs were demonstrated for anystudy cohort.

Multiple Ascending Dose Phase:

The highest incidence of TEAEs was observed at the 2 highest dose levels(4.5 and 6.5 mg/kg/day). The incidence of “possibly-related” events wasalso higher in the 2 highest dose levels. However, due to the smallsample sizes (4 subjects received active treatment in each cohort), itwas not possible to conclude whether the results definitely representeda dose-response. The majority of the TEAEs were not related to studytreatment and were mild in severity with only one event reported asmoderate. The most frequently reported TEAEs for subjects who receivedRIVPA (SEQ ID NO. 5) were General Disorders and Administration SiteConditions (i.e., procedure-related events) such as vessel puncture sitehaematoma, vessel puncture site reaction, and vessel puncture site pain.All vessel puncture-related events were mild and judged to be unrelatedto treatment. Increased alanine aminotransferase (ALT) and back painwere reported by 3 (15.0%) subjects who received RIVPA (SEQ ID NO. 5)and these events were observed by only one (10.0%) subject who receivedthe placebo.

Human Pharmacokinetics

Following IV administration in human subjects and consistent withfindings in animal studies, RIVPA (SEQ ID NO. 5) is cleared from thecirculation within minutes. In the single-dose phase of a healthyvolunteer Phase 1 trial, RIVPA (SEQ ID NO. 5) was rapidly eliminated,with plasma levels decreasing to less than 10 percent of the maximumconcentration (Cmax) within 9 min after the start of the 4-minute IVinfusion. Following the rapid decline, a slower elimination phase wasobserved. The mean time of maximum concentration (Tmax) ranged between˜4 min and ˜4.8 min after the start of infusion for the dose range of0.15 mg/kg to 8 mg/kg. Maximum plasma concentrations and total exposurelevels were dose-proportional and clearance of RIVPA (SEQ ID NO. 5) fromthe circulation was rapid, consistent with the mouse and NHP experience.

In light of the high clearance and short elimination half-life,accumulation following daily injection was not expected to occur. In themultiple-dose Phase 1 study, RIVPA (SEQ ID NO. 5) was administered dailyfor 7 days and the pre-dose concentrations measured on Days 5, 6, 7, aswell as on Day 8 (24 h after the start of infusion on Day 7) were belowthe lower limit of quantitation (LLOQ) for all of the subjects.

Human Pharmacodynamics

In ex vivo investigations using blood samples obtained during the Phase1 healthy human volunteer study, a number of cytokine and chemokineanalytes were quantified after 4 hours of in vitro stimulation of wholeblood with LPS. The inter-individual variability in analyte levels waslarger than any variation in time or response to RIVPA (SEQ ID NO. 5) orplacebo administration and the data were therefore self-normalized usingthe individual pre-dose analyte level to standardize all responses foreach individual subject (the Activity Ratio). RIVPA (SEQ ID NO. 5)effects on the analyte Activity Ratios (ARs) were neither constantthroughout time, nor linearly dose responsive. Nevertheless, in the doserange 0.15-2 mg/kg, there was evidence of an increase in the“anti-inflammatory status” (i.e., higher anti-inflammatory TNF RII andIL-Ira levels coupled with lower TNFα and IL-10 levels after LPSstimulation of blood from each individual).

b. Scientific Rationale for IDR Injection

Mucositis

Mucositis has been linked to the dysregulation of the innate defensesystem, resulting in a cascade of inflammatory action which furtherdamages the mucosal lining and leads to overt mucositis (Sonis, 2004).In particular, while the chemotherapy or radiation treatment causesdamage to the underlying endothelium and epithelium, the response of theinnate defense system to the resulting “DAMPS” results in aninflammatory cascade which exacerbates this damage. Recent studiesevaluating gene expression in animals and humans pre-disposed to intenseoral mucositis have supported the role of the innate defense system inthe disease (Sonis, 2010). Moreover, lower gastrointestinal tractmucositis has also been attributed to similar mechanisms (Bowen, 2008).

Acute Radiation Syndrome

Acute radiation exposure is associated with damage to the epithelium(skin), bone marrow (hematopoietic syndrome) and gastrointestinal tract(GI). Moreover, mortality becomes increasingly acute as the radiationexposure increases, limiting the potential for therapeutic intervention.Early mortality (<2 weeks) after acute radiation exposure is associatedwith damage to the gastrointestinal tract. Acute radiation causes directdamage to stem cells within the base of the crypts of Lieberkuhn,resulting in mitotic cessation and their death through apoptoticmechanisms (Potten 1997a, Potten 1997b). The recovery and/or long-termsequellae of this damage have been demonstrated to be related to boththe GI microbiota and the innate immune repair response (Crawford 2005;Garg, 2010). Ongoing studies on the radiobiology of normal and oncogenictissue have demonstrated a significant role for the response of theinnate immune system to radiation (Schaue and McBride, 2010; Lauber2012; Burnette 2012). Moreover, agonists targeting the innate defensesystem (i.e., TLR-9 agonist) have been shown to be radioprotective inthe GI ARS setting (Saha, 2012).

Oral and GI mucositis as a consequence of radiation tumor therapy servesas a relevant proxy for the GI component of ARS. Consistent with thefunction of IDRs and the role of innate defenses in mucositis, efficacywith IDRs has been demonstrated in a wide array of mucosal damagemodels. In particular, studies in both chemotherapy andradiation-induced oral and gastro-intestinal mucositis have revealedthat IDRs can reduce the peak intensity and duration of mucositisyielding ^(˜)50% reduction in the duration of severe mucositis (FIG. 1,FIG. 2, FIG. 4, FIG. 5, FIG. 6, FIG. 7, FIG. 8, FIG. 16, FIG. 17).

Also consistent with the IDR impact on host innate immunity, efficacy ininfection models has been demonstrated with both Gram-negative andGram-positive (FIG. 9, FIG. 10, FIG. 18, FIG. 19) bacterial pathogens inboth immunocompetent (e.g., FIG. 9) and immunocompromised (leukopenic orlacking T-cells) mice.

IDRs are systemically administered and impact mucosal surfaces (e.g.,oral mucosa, colon [FIG. 3]) as well as the skin and is effective inboth systemic (FIG. 7, FIG. 8, FIG. 9 and FIG. 10) and local Infections.

In summary, IDRs modulates the innate defense response to damage (FIG. 1to FIG. 8, FIG. 16, FIG. 17). Specifically, RIVPA (SEQ ID NO. 5)mitigates damage incurred by radiation (FIG. 1, FIG. 2) and issystemically active, with significant protective effects observed in thegastrointestinal tract in response to chemotherapy (FIG. 3, FIG. 4, FIG.5 and FIG. 6). Moreover, IDRs are efficacious in both immunocompetentand leukopenic animals—suggesting that the hematopoietic impacts whichoccur concomitantly with the GI component of ARS will not impair theefficacy of RIVPA (SEQ ID NO. 5). Given its anti-infective role, RIVPA(SEQ ID NO. 5) may also be efficacious in the hematopoletic subsyndromeof ARS, but the only direct evaluations of this have utilizedsub-optimal intraperitoneal dosing. RIVPA (SEQ ID NO. 5) is not expectedto pharmacokinetically interfere with concomitant therapies and hasdemonstrated no interference with the major classes of antibiotics (datanot shown). RIVPA (SEQ ID NO. 5) does not interfere with recovery fromleukopenia (FIG. 15). In combination with the demonstrated safety ofRIVPA (SEQ ID NO. 5) in human volunteer studies (See 4.a.iv above),these studies strongly support the use of RIVPA (SEQ ID NO. 5) and otherother IDRs treatment in response to acute radiation exposure to reduceacute mortality.

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TABLE 1 all C-terminal amidated unless othe ise indicated**** Net SEQ IDNotes 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ′ Length charge  1 + K S R I VP  6 3  2 Ac denotes Ac K S R I V P  6 2 acetylation  3 + S R I V P A  62  4 + S R I V P  5 2  5 + R I V P A  5 2  6 + K I V P A  5 2  7*denotes D-amino + R I V P A*  5 2 acid  8 + R V P A  4 2  9 + R I P A 4 2 10 Free acid + R I V P A OH  5 1 11 + R A V P A  5 2 12 + R R I V PA  6 3 13 + R K V P A  5 3 14 + R I V P K  5 3 15 + R P V P A  5 2 16 +R P P P A  5 2 17 + R I V P P  5 2 18 + R I V P G G A  7 2 19 + G G I VP A  6 1 20 + G I V P A  5 1 21 + R G V P A  5 2 22 + R I V P G  5 223 + R I V P S  5 2 24 + R I V P L  5 2 25 + R H V P A  5  2? 26 + R I PV A  5 2 27 + R V I P A  5 2 28 + R I I P A  5 2 29 + A V P I R  5 230 + A P V I R  5 2 31 cyclic head-to-tail -R I V P A-  5 1 32cyclic-cystine link -C R I V P A C-  7 1 33 x denotes N-methyl + R Ix VP A  5 2 in backbone 34 x denotes N-methyl + R I V P Ax  5 2 in backbone35 + R I V P F  2 2 36 + Cit I V P A  5 1 37 + R L V P A  5 2 38 + H I VP A  5  1? 39 + I R R V P A  6 3 40 + A R V P A  5 2 41 + I R V P A  5 242 + O I V P A  5 2 43 + S I V P A  5 1 44 + V S I I K P A R V P S L L13 3 45 + K P A R V P S  7 3 46 + R V P S L L  6 2 47 + K P R A V P  6 348 + P A R V P  5 2 49 + I R V P  4 2 50 + R V P S  8 2 51 + R   V P  32 52 + P S V P G S  6 1 53 + G L K H P S  6  2? 54 + R I V P A I P V S LL 11 2 55 See Note 1 X₁ X₂ P 3 56 See Note 2 X₁ X₂ X₃ P 4 57 See Note 3a X₁ X₂ X₃ P 5 58 See Note 4 X₁ X₂ X₃ P b 5 59 See Note 5 a₁ a₂ X₁ X₂ X₃P 6 60 See Note 6 a X₁ X₂ X₃ P b 6 61 + R I V P A C  6 2 62 + r r V P  43 63 hydroxamic acid + R I V P A HOH  5 2 64 + R I V P P A  6 2 65 + R IP A  5 2 66 + R I V Pip A  5 2 67 + R I V Thz A  5 2 68 + R I V Fpro  52 69 + R I V Dhp  5 2 70 + R I H P A  5 2 71 + R I W P A  5 2 72 + R I VP W  5 2 73 + S P V I R H  6 2 74 + C P V I R H  6 2 75 R I E P A  5 176 + R I V P E  5 1 77 + R I V P H  5 1 78 + R S V P A  5 2 79 + E R I VP A G  7 1 80 + K V I P S  5 2 81 + K V V P S  5 2 82 + K P R P  4 383 + R I P  3 2 84 + O V P  3 2 85 + S V P  3 1 86 + K V P  3 2 87 + R RP  3 3 88 + G V P  3 1 88 + K H P  3 2 89 R I V P A Y*  6 2 90*denotes D-amino acid 91 R(tBg)V is linked R tBg V K R tBg V-  8via the side chain amino group of lysine to the valineof another R(tBg)V. 92 mp2 = 4-Amino-1- R I V mp2 A NH₂  5methyl-1H-pyrrole- 2-carboxylic acid ****OH indicateds the free acidform of the peptide. Ac indicates acetylated. O indicated Omithine, Citindicated Citruline, tBG = tert-butyl glycine, mp2 =4-Amino-1-methyl-1H-pyrrole-2-carboxylic acid x indicates NMe backbone(versus amide backbone).

What is claim is:
 1. A method of treating oral mucositis in a subjectwho has been exposed to a damaging amount of radiation orchemotherapeutic agents, comprising administering to the patient aneffective amount of: a) a peptide comprising an amino acid sequence ofup to 7 amino acids, said peptide comprising the amino acid sequence ofX₁X₂X₃P (SEQ ID NO: 56), wherein: X1 is R; X2 is I or V, wherein X2 canbe N-methylated; X3 is I or V, wherein X3 can be N-methylated; P isproline or a proline analogue; wherein SEQ ID NO: 56 if the first fouramino acids at the N-terminus of the peptide, or a pharmaceutical salt,ester or amide thereof and a pharmaceutically-acceptable carrier,diluent, or excipient; or b) a peptide comprising the amino acidsequence of any of SEQ ID NOs: 5, 7, 10, 14, 17, 18, 22, 23, 24, 27, 28,31, 34, 35, 63, 64, 66-69, 72, 76, 77, 90 and 92 or a pharmaceuticalsalt, ester or amide thereof and a pharmaceutically-acceptable carrier,diluent or excipient.
 2. The method of claim 1, wherein the peptide isSEQ ID NO: 5 or a pharmaceutical salt, ester, or amide thereof and apharmaceutically-acceptable carrier, diluent, or excipient.
 3. Themethod of claim 1, wherein the peptide is administered orally,subcutaneously, intramuscularly, intravenously, transdermally,intranasally, by pulmonary administration, or by osmotic pump.
 4. Themethod of claim 1, wherein the effective amount of peptide is at least1.5 mg/kg.
 5. The method of claim 1, wherein the peptide is administeredto the patient every third day during radiation or chemotherapeuticagent administration.
 6. The method of claim 1, wherein the peptide isadministered in combination with an oral dosage form of a topicallyactive corticosteroid or a metabolite thereof to a patient, wherein theoral dosage form is effective for topical or local treatment of thegastrointestinal tract and oral cavity of the patient and furtherwherein the patient exhibits symptoms of inflammation due to tissuedamage arising from radiation or chemotherapy treatment.
 7. The methodof claim 6, wherein the topical active corticosteroid is bedomethasonedipropionate.
 8. The method of claim 6, wherein the metabolite is17-beclomethasone monopropionate.
 9. The method of claim 6, wherein theeffective amount of the topically active corticosteroid is 8 mg/day. 10.The method of claim 1, wherein the peptide is administered incombination with an effective amount of antibiotic.
 11. An isolatedpeptide comprising the amino acid SEQ ID NO. 91 or SEQ ID NO. 92 or apharmaceutical salt, ester or amide thereof.
 12. An isolated peptideconsisting of the amino acid sequence of R(tBg)V1KR(tBg)V2, whereintBg=tert-butyl glycine further wherein R(tBg)V2 is linked via an amidebond between V2 and the lysine amino group in the side chain (SEQ ID NO.91).
 13. An isolated peptide consisting of the amino acid sequenceRIV(mp2)A-NH2, wherein mp2=4-Amino-1-methyl-1H-pyrrole-2-carboxylic acid


14. A method of treating an individual suffering from a disease selectedfrom the group consisting of bacterial infection, mucositis and colitisor exposure to acute radiation comprising administering to theindividual a peptide consisting of an amino acid sequence of Table 1.15. The method of claim 14, wherein the amino acid sequence is selectedfrom the group consisting of SEQ ID NO. 5, SEQ ID NO. 91 and SEQ ID NO.92.
 16. The method of claim 15, wherein the disease is a bacterialinfection.
 17. The method of claim 15, wherein the amino acid sequenceis SEQ ID NO. 91 or SEQ ID NO. 92 and further wherein the peptide isadministered in combination with an effective amount of antibiotic. 18.A method of preventing an infection in a subject, comprisingadministering to the patient an effective amount of: a) a peptidecomprising an amino acid sequence of up to 7 amino adds, said peptidecomprising the amino acid sequence of X₁X₂X₃P (SEQ ID NO: 56), wherein:X1 is R; X2 is I or V, wherein X2 can be N-methylated; X3 is I or V,wherein X3 can be N-methylated; P is proline or a proline analogue;wherein SEQ ID NO: 56 if the first four amino acids at the N-terminus ofthe peptide, or a pharmaceutical salt, ester or amide thereof and apharmaceutically-acceptable carrier, diluent, or excipient; or b) apeptide comprising the amino acid sequence of any of SEQ ID NOs: 5, 7,10, 14, 17, 18, 22, 23, 24, 27, 28, 31, 34, 35, 63, 64, 66-69, 72, 76,77, 90 and 92 or a pharmaceutical salt, ester or amide thereof and apharmaceutically-acceptable carrier, diluent or excipient.
 19. Themethod of claim 15, wherein the peptide comprises the amino add sequenceof SEQ ID NO. 91 or SEQ ID NO.
 92. 20. The method of claim 19, whereinthe peptide is administered in combination with an effective amount ofantibiotic.